Dispelling nutrition myths, ranting, and occasionally, raving


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Will soy give you strong bones? Spoiler: maybe, if you’re a rat

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Recently there was a lot of criticism of a NYT article about what’s making us fat that was really about what diets might make mice fat. Along the same lines is this research from the University of Missouri that found soy diets might increase women’s bone strength.

The study was not on actual human women though, of course. No, this study’s participants were rats. These rats are apparently a good proxy for human women because they are selectively bred to have low fitness levels and, “average American women are relatively inactive both before, and especially after, menopause”. Essentially, both American women (particularly older women) and these rats are lazy so they’re totally interchangeable when it comes to research. As it’s much harder to get women to adhere to specific diets, and there are far more variable to control for and ethical considerations when it comes to human experiments, it just makes sense to use rats.

So, these rats were divided into two groups: one group was fed a corn-based diet (you know, just like the average post-menopausal American woman eats) and the other was fed a soy-based diet. The results showed that: “the tibia bones of the rats that were fed soy were stronger compared to the rats who were fed the corn-based diet, regardless of ovarian hormone status”. Leading to the conclusion that: “Bottom line, this study showed that women might improve bone strength by adding some soy-based whole foods to their diet”.

To recap: rats were fed either corn-based rat food or soy-based rat food. The rats fed the soy-based rat food were found to have stronger leg bones. Therefore, human women can increase their bone strength by eating more soy.

This is ridiculous. We are not rats. We do not live the same lives as laboratory rats. We are not all sedentary. We do not eat the same food as laboratory rats. It is a huge leap to say that this study in rats shows that consumption of soy by women can lead to stronger bones. We are not eating a homogenous diet of corn-based rat food. The forms of soy we consume as humans are very different from that in rat food (e.g. tofu, soy beverage, tempeh, edamame, TVP).

Perhaps soy-based foods can increase bone strength in humans but this study doesn’t tell us that. This study tells us that this breed of rat has stronger bones when fed a soy-based diet than when fed a corn-based diet.


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Of doctors, nutritional nonsense, and tweets

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I stumbled across a tweet from a doctor in the US last week and was so surprised by it that I did a little Internetting to determine if this tweeter was a licenced MD. Yep, she was. Now I’m not going to use her name because, perhaps (although based on Rate my MD, it seems unlikely) she’s a far better physician than she is a tweeter. My aim is not to attack her. My aim to to combat the outrageous information she’s tweeting. So… What’s she been saying?

The first tweet I saw said:

… Along with flax seeds, throw some China seeds into smoothies or yogurt. No flashes!

Wow. Who knew, all you have to do to prevent hot flashes during menopause is to include chia (I assume that’s what she meant by “China” – hey, typos happen to the best of us!) seeds in our diets. Is this true? Maybe. Although I’m highly doubtful that it’s that simple and as far as I can tell there’s been no published research on the subject. There are some studies of chia and weight loss in post-menopausal women but none investigating the effect of chia seed consumption on hot flashes during menopause. There is some anecdotal “evidence” on the Internet extolling the benefits of chia seeds for reduction/elimination of menopause symptoms. And while there’s certainly nothing wrong with incorporating chia seeds into your diet at any stage of life, no sensible health care professional would be providing this unsolicited, unsubstantiated advice on social media.

Scrolling through the docs timeline I came across a few other gems. How about?:

Those of you with hypothyroidism should be taking iodine and selenium supplements to help the conversion of T4 to T3.Helps metabolism

Um. No. The only reason for those with hypothyroidism to take iodine supplements is when the condition is caused by iodine deficiency, which is rare in North America (1). There may be benefits to selenium supplementation for those with hypothyroidism. However, there may also be risks associated with long-term supplementation and supplements should be discussed with your primary health care practitioner, not undertaken upon the advice of a tweet.

There are more horrifying tweets but I have to stop somewhere. One last one:

HIgh cholesterol? You are eating too much refined carbs ie #BREAD, white rice, potatoes and not enough fat ie #butter, fatty fish.#krilloil!

High cholesterol has many causes. Not least of which is heredity. Yes, there are lifestyle efforts we can all undertake to reduce our risk of elevated LDL (low density lipoproteins AKA “Bad cholesterol). However, these will only go so far and some people can lead extremely healthy lifestyles and still have high LDL. While it’s likely that saturated fats are not the evil, cholesterol raising nutrients we once believed them to be there is also no reason to think that increasing consumption of them will reduce blood cholesterol levels. The evidence is not there to support supplementation with krill oil either. As for the refined carbs the doctor lists, unless she’s referring to potato chips or french fries there’s no reason to diss potatoes. In fact, potatoes are one of the most under-rated foods.

Guys, be cautious. You’ve all seen Doctor Oz. He’s not the only doctor spewing nutrition nonsense. Question everything you read.